Acronis TIH 2010 registration

I bought a "used" copy of TIH 2010. I like that version better than the newer ones, and it's nice to have all my home computers use the same version (since I'm the de facto IT manager here).

The previous owner's computer died a while ago, and he isn't using the license any more. I was able to install the software and activate it successfully with the old serial number, but I am unable to register the serial number under my account at acronis.com, since he had already registered it. Is there a way to "move" the registration? This is a minor issue, but it would be very nice to have it listed with my other licenses when I log on to my account.

Thanks for any help or suggestions!